Muwatta Malik 1046

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ ثَوْرِ بْنِ زَيْدٍ الدِّيلِيِّ، عَنْ عَبْدِ اللَّهِ بْنِ عَبَّاسٍ، أَنَّهُ سُئِلَ عَنْ ذَبَائِحِ، نَصَارَى الْعَرَبِ فَقَالَ لاَ بَأْسَ بِهَا وَتَلاَ هَذِهِ الآيَةَ ‏{‏وَمَنْ يَتَوَلَّهُمْ مِنْكُمْ فَإِنَّهُ مِنْهُمْ ‏}‏‏.‏

Yahya related to me from Malik from Thawr ibn Zayd ad-Dili that Abdullah ibn Abbas was asked about animals slaughtered by the Christian Arabs. He said, "There is no harm in them," but he recited this ayat, "Whoever takes them as friends is from them." (Sura 5 ayat)

Reference

Muwatta Malik 1046

In-book

Book 24, Hadith 5